Ontario is set to vastly expand the powers of the provincial Ombudsman, allowing the independent watchdog to investigate municipalities, universities and school boards, The Globe and Mail has learned.

The move will be part of a sweeping new Accountability Act, which will put in place transparency measures across the provincial government, a source with knowledge of the proposed law said. The bill, to be unveiled Thursday by Premier Kathleen Wynne and Government House Leader John Milloy, will be tabled in the legislature later this month.

WATCH

The act will create more oversight in government agencies, the source said, with a series of measures for different government departments. It is also expected to include new accountability rules for politicians, including MPPs.

Ombudsman André Marin has long argued that the province shields too many agencies from his scrutiny, giving people who have problems with them no independent office to call for help.

The bill will at least partly satisfy his demands. It will not, however, allow him oversight of the health-care sector, something he has long sought. Instead, the law is expected to create a different transparency mechanism for health. A hard-biting watchdog with a knack for drawing public attention to problems and mistakes in the province, Mr. Marin has long been a thorn in the side of the government, which may help explain why Queen’s Park has often been reluctant to grant him more latitude.

But giving him the right to look into municipalities and local agencies, in particular, will represent a massive expansion of his role, allowing him into a whole new level of government. Most municipalities in Ontario do not have independent watchdogs of their own, meaning the new rules will expose them to an unprecedented level of scrutiny.

People with complaints about their local government or school board, as well as university students, will now be able to ask the Ombudsman to help resolve them. Mr. Marin will also have the power to launch investigations into systemic problems in municipalities, universities and school boards, and make recommendations on how to fix them.

The province’s move comes on the heels of several major municipal controversies in recent years. London Mayor Joe Fontana is facing fraud charges. In Brampton, Mayor Susan Fennell is the subject of an audit after she and her staff spent $185,000 on airfare and hotels in the past five years. Brampton councillors, meanwhile, are also in the spotlight for using tax money to pay for symphony tickets and home security systems.

And in Toronto, Mayor Rob Ford was nearly ejected from office for using city letterhead to solicit donations to his football team from lobbyists.

Mr. Marin has accused some municipalities of secrecy for holding meetings behind closed doors. In one particularly damning report last year, he concluded that a group of London councillors had violated provincial law by holding a “back room” meeting at a restaurant a few days before a budget vote. Mr. Marin currently has some limited powers to investigate municipalities, but councils have the right to opt out of his oversight.

In Toronto, one of the few cities in the province to have accountability officers of its own, the city Ombudsman will take precedence over Mr. Marin, but will have the power to call in her provincial counterpart to help on investigations.

In recent years, Mr. Marin’s probes have targeted everything from the mass arrests at the Toronto G20 summit to jail guards that beat prisoners to over-billing of customers by Hydro One.

It is not clear when the Ombudsman’s new powers would come into effect. Ms. Wynne’s Liberals control only a minority of seats in the legislature, meaning they will need the help of at least one other party to pass the law.